Brake-operating device for trailers



A. L. PARRISH BRAK OPERATING DEVICE FOR TRAILERS Oct. 20

2 Sheets-Sheet 1 Filed March 3l,

oa. 20,1925. 1.551.770 A. L. PARRIsH l f BRAKE OPERATING DEVICE FOR TRAILERS Filed Marth 31. 1923 2 Sheets-smut 2 Patented Oct. 20, 1925.

UNITED STATES ANDREW'L; mamen, or LONG BEAGH, GALIFQRNIA. i g1 BRAKE-PERATING DEVICEFORTRAILERS. I I

Application mea Marcial, 1923. semaine. certezza.Y

be provided. with independent braking means controllable from the leading unit of the train. However, the extent of application of thisr principle inA theI automobile trailer field has been .very limited, due mainly to the lack of ei'cient trailer brake control mechanism. The consequent widespread use of unbraked, and therefore uncontrolled automobile trailers, `has developed-into more orless -of atrafiicmenace. In checking the speed of such trailers, the entire braking strain of the train is concentrated on the brake drums vof the leading vehicle, a strain which often results in accident.V In other words, the factthat one unit of the train is out of controlTmay easily result in throwing the entire train out of control.

Many different means for couplingleadg p y y A yinvention comprisesthev provision of three ers and trailersjhave been devised, but the constant tendency of unbraked trailers to creep up on the leader'when the speed of .the-platter Vis checked, causes undue and eX- ccssive wear on the coupling, no` matter how excellent the` design of such coupling may be.

Therefore, it is .myprincipal purpose to provide novel, practical andl eificientnieans operable from the leading vehicle for bringing automobile trailers under ,the complete control of an operator on the leading vehicle.

It. is further one ofrmyob'jects lto provide a flexible trailerbrake controllingl means whereby relativelateral,vvertical or swingingv movement between leader and trailer.

will not interfere with the effective operation of the trailer brakes.

` Further objects of my invention will be more particularly described in connection with the accompanying drawings and detailed description.v v y Y .Tn the drawings: 1

Fig. V1 is a side elevation of an automobile truck Vand trailercouple-dtov form atrain, showing my devicel attached thereto; l f Fig. 2 is'a'top'planA View: of Figure 1; f

Fig. 3Nis a view yshowing :method of mounting lthey Vn riinding drum of v"my" fdevice; Figgii isa'selctionwon line ofuFig- `ure 3;

Y' Fig. a'sectio'n ',c-bnfliney '5f-f5 ,ofFigure Vshowingthedrum rotating'pawl inoperative engagement w'ithithe: drum;l

Fig.6 is an'A eQlarged'fragmentafyi-plan view ofthat portion of Yanydevice attached to the trailer.

. For thefpurpose ofillustrationflhave shownmy brake controllingfneans fas being attached to and "extendingl between an'. automobile truck`1`0 (hereafter referred tol` the Ileading xyehicle or 'leadel-coupjled at 9 un'derstecd that they' invention 'may beapleading'v vehicle and any `ofythewell known types of trailers, such as' theftwo-wheeled dolly7 or theA four-wheeledtracking truck. I .have indicated at 12 thejusualltruck traction i'wheels, while the. forward andffrear ,wheels of trailer'll fare designated at 13 and I1&1, respectively.,

11.1 .jgelierah a practlcalembodinient oflmy connectedy groups ofllassociated elements, each group performing afdlstmct'function Vto a four-wheeledtrailer:11;,fb11t it'will be y.

in thelgbraking operation.-V Thel first `group g, setcomprises ,brake bands :co-actingin the usual manner withy :brake drums on lthe 'trailer lwheels {or axle andoperativeconnections between ,suchfbrake"fb'andsj ',and,fthe 'second i group! whi comprises brake Vapplying tinggand releasinglmeans carried by ,the

trailer. The third group 'consists of controlling meansv locatedyonv theleaidi-ng l vehicle and. operative connectionsbetweenthe control means and ytheV aforementionedsecond group.

Trailer brakes generallyfindicated aty .15 i

may consi'stof brake bands 1.5*LY adaptedlto frictionallyy co-actlin the usual,inanner with brake drums 16 carried by trailer wheels 14.

Pull rodsv 17 areoperatively :connected to bandslZ1 by vs uch'in'eans as cranks 18 wherelongitudinal-movement ofthe pull rods shifts bandsvla withI respecttodrums 1'6 to cause brake application or' release; Rods/1T are connected to cranks 19 mounted on coaxial rock shafts 20 and 20a, the inner ends of the shafts meetinfr. and having bearing iny angle member" 21 the vertical leg 21" of which is attached to the trailer frame at 21, for instance) and the outer `ends of rthe shafts being journaled in the: hangers 21 depending from the side frame members of trailer 11. The elements just describedare more or less conventionally shown', vsince they may vary considerably in construction to fit the various types of'trailers. Brakes 15 may be o f any desir-ed type such as internal-expanding or external-contracting.

lever or brake-bar 23 is'fulcrumed at 24 to frame 22 and Vis Vconnected to rock-shafts 20 and 2O by such means as the equalizer generally indicated at 24a whereby radial movement limparted to lever 23 rocks shafts 2() and`20?, Equalizer 24a includes pull rod 25% which is 'pivotallyconnected at one end Yto lthe center of bar 25 and at the other end to lever 23. Links or rods 26 are pivotally connected to bar 25 and the' "shaftv carried cranks 27, the bar being adapted to slide over horizontal leg 2 1cl of member 21a when pull rod 25a is 'reciprocated during oscillatory movement of lever 23. Y

"A-locking bar 28jconstruct`ed in the form of 'a notchedsector is. secured to cross yframe members 22a at29 in concentric relation to the fulcrum point 24 and is arranged to be traversed by lever 23 when v the latter is 'radially moved. A paivl 30 is'pivotally arranged with ren spect to lever 23 as at 31 and is normally held in engagement with'sector teeth 32 by 'such means as spring 33 which is secured to lever 23 as at 3 4, The (zoaction of spring 33 with pawl 30 normally allows a clockwise movement of lever 23 with respect to fulcrum point 24 and .prevents a counterclockwise movement thereof.

. 'Acontractile spring 35 extending between and having its opposite ends secnred'to lever 23 and one of the cross members 22a at'36 and 37 respectively, tends to swing lever 23 in a counter-clockwise" direction, the brakes 15 being in full release when lever 23 is at the limit of its counter-clockwise travel.

Bell crank 33, havingone arm 39 thereof fulcrnmed to lever 23 at 40, is pivotally'connectedl at 41 to pawl 30 in such a manner that clock-wise movement of crank 38 retracts Vportion 43 extending through an aperture 44 paratively taut.

of registering outline provided in bracket 45, a nut 46 threaded on shaft 42 serving to clamp theshaft Vto the bracket. Bracket45 may be secured to body 47 of truck 10 by such means as bolts 48. f

A hollow drum 49 is rotatably mounted on vshaft .42, being retained thereon by nut 50 threaded on the free extremity of shaft 42.

A cover )late 51 is removably secured to drum 49 y such means as nuts 52 threaded on bolts 53, which bolts extend from the opposite sideplate 54.

A Vbrake ap lying cable 55 has one exlremity thereo fastened to the lever 23 as at 56 whence it passesfthrough guide clip or loop 57 onf trailer 1 1 and similar' clips 58 providedion'trnck 10. The cable is the-n preferably ygivenone or more turns about drinn 49 and its extremity passed through an apertnre59 in the face of drum 49 and 'se- Ydrum 49, one extremity of said spring being anchored at 63 to the fixed shaft 42 and the oppositeextremity being secured at (34a to drum ,bolt 53".' In assembling the Adsrnni 49 and yspring 62 and operatively connecting the cables 55 and 60 toy thedrum, spring 62 is placed under aninitial tension adapted t'o impart a constant tendency on the part of drum 49 to rotate on shaft 42 ina clockwise direction. l

Spring (52 is relatively weak with Vrespect to spring 35, but is of suflicient strength to compensate for any relative movement between t'ruck 10 and trailer 1-1 by yielding or takin'gsup to maintain cables and (SOcom- Spring 62 'also serves as a slack take-up means during the operation of the i Vdevice as hereinafter described.y The strength of spiralspring 62 is greater than "that of spring 33, for a 'reason which will later be apparent.

-Druin 49, or the plate 54 carried thereby,

.is provided with the peripheral teeth 64.

An operating lever 65 is journaled on shaft 42 ,adjacent the drum 49, the swinging move- 'mentof said iever being limited by Stop 66 projecting laterallyk from truck body 47, since drum 49 and lever (S5 are each independently rotatable on shaft 42, they may be described as normally relatively rotatable or movable.

' A -driving'pawl 67 is pivoted on lever G5 at 63 and is adapted to co-act with teeth 64. A pull rod 69 having a grasping handle 70 is linked tol lever 65 as at 71 and passes through a guide stra-p 72 secured to levei 65 at 73. The lower extremity of rod 69 is pivo-tally connected to pawl 67 as at 74. lawl 67 is normally held out of engagement with teeth 64 by means of van expansive spring 75 which encircles rod 69 and is interposed between guide 72 and the pawl 67.

A brake releasino lever 76 is jouriialed on shaft 42 intermediate the lever 65 and bracket 45 and is preferably constructed in the form of a bell crank, one arm77 of which terminates in a pedal 78 and the other arm 79 carries a pin 80 secured thereto by nut 81. A grooved roller 82 is rotatably mounted on pin 80 and is capable of a slight lateral sliding movement thereon in order to allow said roller to follow cable 60fas'it is kbeing wound or unwound with respect to drum 49.

Roller 82 is immediately superposed by the cable 60 and is normally maintained in light engagement therewith, a stop 83 carried by body 47 performing this function by limiting' the countereclockwise movement of lever 76 as viewed in Figure 5. i

Assuming that the brakes 15 are released and the. truck operator desires to make a trailer brake applic-ation, he will grasp the leve-i' 65, including in his grasp the handle 70, thus drawing such handle towards the lever 65. This action, through the medium of link 7l and rod 69, results in pawl 67 being forced into engagement with teeth 64 as clearly illustrated in Fig. 5, the pawl thus functioning as `releasable'means forinterconnecting lever 65 and drum 49 to hold them against relative rotation or movement.

By then imparting a clockwise swing (Fig. 4) to lever 65, pawl 67 rotates drum 49 in a clockwise direction, thus winding the cable and 60 onto'drum 49, the .spiral spring 62 aiding rather than resisting Vsuch clockwise rotation. 1 i s' The just-described winding up of cable causes a consequent `clockwise swing of lever 23 (as viewed in Fig. 6) landV thus serves to apply brakes l5 through the medium of equalizer 24a, rock shafts 2O and 20a', cranks 19 and pull rods 17.

Since release cable is traveling or being vwound on drum 49 ywith Ia. speed exactly equal to that of applying cable 55, there is no consequent relative movementjbetween bell crank 38 andl lever 23, paw/130 being left free to ratchet over sector teeth 32.

Upon securing the desired degree of brake application, the truck operator is free to re lease his grasp on lever and handle 70, whereupon spring servesv to withdraw pawl 67 from engagement with teeth 64. However, the engagement of pawl 30 with sector teeth 32 prevents the counter-clockwise movement. (Fig. 6); of lever-23 and cables 55? and y60 in a relatively taut condition vafter the operator-loosens his grasp onV handle 70.l

When it is desired to release the brakes l5,

the operator exerts a :foot pressure-"on pedal 78, thus swinging release lever 76 in a counter-clockwise direction (as viewed in `Figure 4) and swinging roller 82 upwardly toy exert an additional tension on release cable 60,

lcable 55 being unaffected by such movement. AContinued pressure on :pedal v78 results iii shortening the effectiveileng'th of cable 60, or, inf other words, exerts'y a'pull or additional take-up on said cable. Since the yinertia of'V drum 49 andthe spring 62tends tion of drum 49, the "spring 33 mustyield,

allowing bell crank f38t0 be pulled in 'a clockwise direction (Fig.6)-and causing` the retraction of pawl 30 from engagementl with',

sectorV 32.. Spring then acts to swing vleverv 23 in a counter-clockwise direction ladditional tension-and allowing spring 33- to again cause co-action between pawl 30 and' sector 28.V The brake control mechanism is thus returned to normal, brake-reY lease position, ready t0 be actuated to cause a succeeding brake application. I have provided a safeguard for positively disengaging pawl'67 from teeth 64 under certain conditions. For this purpose,l I

haveextended pawl -67 to'form a nose cam 85' and have'positioned a bar 86 in the path 80 to yresista counter-clockwise (Fig. 4).rota

eisV

of cam 85 by Vmeans of a standard 87, the

latter being adjustably secured to bracket 45 by bolt 88.y As truck l0 isturned to thev right (Fig. 2) the distance between drum 49 and lever 23' is increased'over that of normal since the change of direction ofthe traileris delayed with respect to that of the forward end of truck 10 where thel drum 49 is located. v( 'Spring` 62 yields to the Aresulting increased tension, drum 49 being coin-V cidently revolved in,` a counter-clockwise direction (Fig. 4). Should it happen that the operator were applying thetrailer brakes 15 during such a period, -it will be seen that such drum rotation would, throughv the coaction of teeth 64 and pawl 67 swing lever 65 in a counter-clockwise direction against 'the pull exerted by theoperatorthereon.

Such vopposed effort mightl readily result in accidentftoA the drum mechanism or the Hoperatoi"s hand were it not for'tlie provision of nose 85 and bar 86; However, the ycoaction caused between such nose andk bart during suchV movement of lever 651 rotates paivl 67 about pivot-68 and thus positively retracts said pawl from engagement with teeth 64, preventing further movement of the ylever 65 but allowing drum 49. to further revolve. Y

vSince it is customary tol incouple trucks and trailers during the 'loading and unloading of the trailers, it is desirable that the trailer brake connections extending between truck and trailer be readily disengaged and :re-engaged. Y Therefore, cables and GO are provided with. hook and eye connectionsV 89 whereby they may be parted to `allo1 the uncoupling of the trailer from the truck. The hook and eye terminals may f then be looped through guides 57 and 58 to temporarily support the free endsof cablesv and 60 and retain themreadily accessible forY lreuniting.v Y

It will be understood thatv a plurality or series ot trailers similar to l1 may be couypled behind leader 10 with independent brake applying apparatus, similar tothat just described, mounted on each trailer all of such apparatus being operatively connected to one or more control drums mountf ed on the leader.

f and a'li'ailer coupled thereto, brakes operatively connected to the Wheels of the trailer, brake applying means carried by said trailer and connected to said brakes, brake setting means on said trailer adapted to co-act with said applying means to retain brake application, control means'carried by said leading'vehicles and adapted to be selectively operated, a flexible member operatively connecting to said applying means and said control means, means on said trailer adapted to release said setting means, a sec- A \ii l,lle \;il)lc member connecting' said releasing means and said control means whereby selective actuationk of the con-trol means is kadapted to-.operate said applying and reflexible means operatively` connecting said applying means. and said control member, further flexible means operatively connecting said releasingfmeans and said control means, and yieldabletake-up means adapted toco-act with said control means in a manner to retain said flexible means in a taut condition.

1l. In combination with a leadingI vvehicle and a trailer coupled thereto, brakes opera-l tively'connected to the Wheels of the trailer, a brake lever fulcrumed on said' trailer and ,connected to said brakes, means adapted to yieldably maintain said lever in brake-rclease position, a drum rotatably mounted on the leading vehicle, a cable connecting ysaid drum and said lever, and means for .rotating said drum to take up said cable in a manner to `swing said lever into brake-applying position.

5.111 combination with a leading vehicle. and a trailer coupled thereto, brakes operatively connected to the Wheels of the-trailer, a brake lever fulcrumed on said trailer and connected to said brakes, means adapted to yieldably maintain said lever in brake-release position, a drum rotatably mounted on the leading vehicle, a cable /connectingsaid drum and saidlever, means forrot'atingsaid drinn to take up said cablein a manner to swingsaid lever into brake-applying .position, a locking bar on said trailer, and setting` means carried by said leve-r adapted to co-act with said locking bar in a manner to retain said lever in brake applyingl position.

6.l In combination with a leading vehicle anda trailer coupled thereto, brakes operatively connected to the Wheels ofthe trailer. a brake lever fulcrumed on said trailer and connected to said brakes, means adapted to yieldably maintaiiirsaid lever in brake-release posit-ion, a drum rotatably mounted on the leading vehicle, a cable connecting'said drumrand said leven-means for rotating said ydrinn to take up said cable in a-inanner to swing said lever intobrake-applying position, a locking bai' on said trailer, setting means carried by said lever adapte-fl to coact with said locking bar in a manner to retain said lever in brake applying position, release means carried by said lever and connected. to said setting means, a vrelease cable connecting said drum and said rcleaf-e means and/arranged to be Ltaken up equally with the first-mentioned cable upon the rotation of said drum, and means adapted toco-act with. saidl release cable Vto further .and

separately take upsaid release cable lin, a` manner to actuate saidrelease means tol cause the withdrawal of said setting means from co-action withsaid locking bai'. Y

7. In a trailer brake control'mechanism, :i

ulcrumed brake lever operatively connect-- ed to Athe trailerbrakes, yieldable meansv to cause yco-acting engagementbetween said operating lever and said drum whereby movement of said operating leverrotates said drum in a manner to wind said fiexihle` connecting means thereupon and thereby move said brake lever intobrake-applying position, and brake setting` means independent of said drum and adapted to co-act with said brake lever to retain said brakelever in brake-applying position whereby said' operating lever is capable of beingvsubse quently disengaged from said drum without affecting said setting means.` 1

S. In a trailer brake control mechanism, a fulcrumed brake lever operatively connected to the trailer brakes, yieldable means adapted vto normally maintain said lever in brake-release position, a rotatable drum, flexible connecting means between said drum and said lever, an operating'lever-normally.

disengaged from said drum, means adapted to cause co-acting engagement between said operating lever andv said drum whereby movement of said operating lever rotates said drum ina mannerto wind said flexible connecting means thereupon ,and thereby move said brake levei' into brake-applying posit-ion, brake-setting means independent of said drum and adapted to co-act with said brake lever to retain said brake lever in brake-applying position` whereby said operating lever: is capableyof rbeing subsequently disengaged from said drum without affecting said setting means, and- 'means adapted to retain said flexible connecting means in a 'ta-ut condition after-such vsubsequent disengagement@ i l 9'. In a trailer brake control mechanism, a brakev lever operatively connected to the trailer brakes, yieldable means adapted to normally maintain said lever in brake-ref lease position, a rotatable drum,.flexible connecting'means between said drum and said lever, an operating'lever adapted to engage saidy drum whereby movement of said operating lever rotates said drumv in amanner to wind said 'flexible means on said drum and thereby move said :brake lever into. brake-applyingposition, vbrake setting'means adaptcdtoco-act with said brake lever to retain said brake lever in brake-applying posit-ion, flexible brake-releasing connecting means between said drum 'and said settingV means adaptedto be woundon said drum upon rotation thereof, and means adaptedl to impart an additional tension to said re leasing connection whereby'said setting means is actuated ,to allow vsaid yieldable means to return saidvbrake lever to brake. release position, y f

10.1In atrailer brake controlmechanism, a brake 4lever operatively connected to the trailer brakes, fyieldable,y means adaptedr to,

normally maintain said lever; inbrake-release position, a rotatable drum, iexible con. necting means between said drum and said lever, an operating lever adapted to engage said drum,y whereby kmovement of said operating lever-.rotates said drum in a manner to wind said flexible means on said drum and thereby move said brake lever intoy brake-applying position, brake settingineans adapted toco-act with saidbra-ke lever tof retain said brake lever in brake-applying position, flexible brake-releasing v connecting means between said drum and said setting means and adapted to be wound on said drum upon rotation thereof, means cofacting with said drum andv adapted Vto normally maintain both of said flexible connecting means under uniform tension,` and means adapted' to impartan additional tension to said releasing connection wherebyvsaid setting meansis actuated to allow saidryieldable meansv to return. said brake lever to brake-release position. Y Y, v 1l. In combination withpa leading vehicle and a trailercoupled thereto, ,brakes opera-r tively connected to the wheels of the trailer, brake applying-means on lthe trailer, releasable .brake setting means i on thetrailer adapted to coact with said applying means to Vretain brake application, a flexible ,member connected to the applying means, said flexible member leading to ,and being ioperable from the leading vehicle, means'on the trailer adapted to lrelease said setting means, a secondflexible member connected tojthereleasing means and extending to and being operable from the leading vehicle, and yieldable take-u means adaptedto maintain said flexible members Jin taut condition.' y z Q f @12. In combination with-a leading. vehicle and a.- trailer coupled thereto, brakesoperatively' connected to the' wheels ofl the trailer, brake applying means onI the trailer, flexible connective'means betweenthe applyingmeans and the leading vehicle, means on the leading vehicle for vexertinga pull on'l the connective means jto effectbrake application, releasable brakesetting means on the trailer and @adapted to` retainA brake application, flexible connective means between thegsetting meansV andv the leadingl vehicle,l Ayieldalzile l'lO connective means toflexible eenneetivemeans between the apr p'lying means and tlie'leading vehicle, meanson the lleading yehi'el'e for exerting apull on tlie Connective means tol'eieot brake ap` plieation, releasab-le brake setting ineens on tlietrailer and adapted to retain brake ape plioatj-ion, flexible ootlneetive means btvveen the setting means and the leadingyehole, yieldable talteqipineans iermaintainiiig tlie tworonneoti've means 'in a taut eondition, and' mea-'iis for moving the second Cofnneotifve means independently of' the first oonL neetiv'e means to release said brake setting means.

14. In at'rai'lerbr-ake 'control mechanism, a brake lever o'perativelyy connected to the trailer brakes, yieldable means adapted to normally -niaintain said lever in breiterelease position, a rotatable 'd1-ain, flexible eonnetting means between said drinn and said lever, an operating lever adaptedto engage said driini' whereby movement of said opere ating lever in one direction rotates said drum in a ina-nner to Wind 'said flexible means on said dif-nm and thereby nieve said brake lever into brakeia'pplying position, brake setting mea-ns adapted to eoaet with said brake lever to retaiii'sai'cl brake lever in abrakefapplying position-,`flexi ble brakeneleasi-ng 'conn'eoting mean's lbetween 4`said drinn and said setting means adapted to Vbe' Wound on said drinn upon rotation thereof, ineens adapted toinipart an additional tensi'on to said releasing connection whereby said sett-ing means is aet'uated to allowsaid yieldable means to return said brake lever to brake-release position; and means for disengaging the operating lever from the drinn Wl'ien 'tlfe leveris V'move'd in the opposite direction. l

l5. In Combination With a leading yeliiele and a trailer 'Coupled there'to,l a brake lever operativelyy connected to the trailer brakes', a pra-ir o f relatively movable memberson the vleading vehicle,`'rel'easable means for interconnecting said members' to hold them Iagainst relative movement, yieldableineans normali-y adapted to hold said` releasable means in operative positionnieans adapted t'o niove said releasable means-@into operative interconnecting position; iexible connecting ineens between said brake lever and one `of said members whereby,- vvhen t said -releasable means is in operativev position, movement in ene direction 'of said one meniber by 'irrevenatmvvoA ment of tlielothermember eileets a pull on the flexible means to move the brake lever to brake applyingV position, and means adapted to coast Witlian'd return said re` leasable means to inoperative position when said other member is subsequently moved in theopprosite direction, Y

16. In' combination with a leading vehicle and a trailer Coupled thereto, brakes opera tively connected to the Wheels of the trailer,

brake applying means 'on the trailer, a drinn rotatably mounted onthe'leading vehicle, a cable oonneotingsaid drum and said brake applying' means, inea-.ns for rotating the drum to take up said Cable in a manner-to operate 'the brake vapplying' means, .releasable setting means on the trailer for retaining brake application, a release cable oonnesting said drum andsaid release means andl arranged to be taken up equally-With the first mentioned cable upon rotation otl the drum, and means for taking the release cable up independently of the other Cable and thereby releasing 'said setting means.

17,. in ooinbination with a leadingveliiele 'and a trailer coupled thereto, brakes operatively connected to the Wheels of the trailer, brake applying means on the trailer, a rotatable drum on the leading vehicle, a cable eom'ieeting the drum and applying means, releasable manually operated means for 'rotating the drum in one directiolito` means, relatively strong Yspring on. thev trailer, said spring being normally adapted to maintain the brakes in release position t and yieldably resisting movement oi` the cable in one direction and thereby resisting rotation of the drum in 'one direction, a relatively Weak spring on the leading vehicle and adapted to yieldably resist rotation ot' the dlrnm in the opposite direction, releasable manually operated means on the lead-` ing vehicle adapted to rotate thedrum in said one direction to ltake up the cable and thereby operate the applyingmeans,l brake setting means on the trailer and adapted to retain l the brakes in vapplied condition against the action of said stronger spring, and, When the brakes are so, retained and when. the mamiallyoperated means is out,l of operation, the weaker spring being adapted to rotate the drum in said one direction to take up slack as it develops in the cable and yielding to allow rotation of the drum in the opposite direction to pay out cable when separative movement occurs between leading vehicle and trailer.

19. In a trailer brake control mechanism, brakes operatively connected to the wheels of the trailer, brake applying means on the trailer and connected to the brakes, arotatabl'e drum, flexible connecting means between said drum and applying means, means for rotating the drum to wind said cable thereupon and thereby operate the applying means, releasable brake setting` means adapted to retain application or" the brakes, flexible brake releasing connecting means between said drum and said setting means, said releasing means being adapted to be wound on the drum upon rotation thereof, a spring coacting with the drum and adapted to maintain both of Vsaid connecting means normally Linder uniform tension, and means adapted to impart additional tension to said releasing connection for moving the setting means to release position.

20. In a. trailer brake control mechanism, a rotatable drum, a cable secured to the drum and operatively connected to the trailer brakes, a spring adapted to rotate said drum in a manner to yieldingly take up the cable, and disengageable and manually operated means for rotating the `drum in a manner to take up the cable positively.

2l. In combination with a leading vehicle and a trailer coupled thereto, brake applying means on the trailer and operatively connected to the trailer brakes, a rotatable drum on the leading vehicle, a cable operatively connecting the drum and brake applying means, and a spring on the leading` vehicle adapted to rotate the drum in one direction in a manner to take up the cable when slack develops therein and to yield and allow the drum to rotate in the opposite direction when separative movement occurs between leading vehicle and trailer.

22. In combination with a leading ve-V a rotatable. drum on the leading Vehicle, a.

cable connecting said drum and brake releasing means, a spring coacting with the drum for yieldingly resisting its rotation in one direction and thereby maintaining the cable in a taut condition, and means adapted to take up the cable between the drum and setting means and thereby release they setting means.

23. In combination with a leading vehicle and a trailer coupled thereto, brake applying means on the trailer and operatively connected to the trailer brakes, brake setting means on the trailer, a relatively weak spring adapted to maintain the setting means releasably in operative position, a rotatable drum on the leading vehicle, a cable connecting the drum and the setting means, a relatively strong spring coacting with the drum for yieldingly resisting its rotation in one direction and thereby maintainingl the cable' normally under predetermined tension, and means between said springs adapted to tension the cable with added force, thereby withdrawing the setting means from operative position against the action of the weaker spring.

In witness that I claim the foregoing' I have hereunto subscribed my name this 19th day of March 1923.'

ANDREW L. PARRISI-I. 

